Web Viewer gradually slower and eventually resets it self
Problem
Web viewer gradually gets slower over a period of time, and also simple tasks take considerable time. Gradually the web viewer gets so slow that it stops responding. Eventually a restart of IIS is triggered which brings back web viewer to normal behaviour. Process repeats.
Solution
For sites with a large database and a lot of visitors, caches can build up and consume a lot of memory.
Check if the IIS worker process consumes a lot of memory.
A high memory consumption is not a problem, provided that there is sufficient memory on the server. Check available memory on the server.
Also verify that the application is running in 64 bit mode (and not 32 bit) in IIS. If running in 32 bit mode also a fairly low memory consumption can be too high and trigger bad behaviour.